The present disclosure relates to the subject matter disclosed in German application No. 102 13 777.3 of Mar. 22, 2002, which is incorporated herein by reference in its entirety and for all purposes.
The invention relates to a machine tool comprising a machine frame, a tool carrier with a tool carrier housing and a tool carrier head which is mounted on the tool carrier housing for rotation about an axis and has a support member with a plurality of tool receiving means, into which drivable tool units can be inserted such that gear wheels for driving all the tool units insertable into the tool receiving means are arranged in an interior of the support member on an orbital path extending around the axis and can be moved on the orbital path during rotation of the tool carrier head, a tool drive with a drive wheel which is arranged in the interior of the support member, can be driven by a drive motor and with which at least one of the gear wheels can be driven.
Machine tools of this type are known, for example, from German patent application No. 199 19 238 A1.
The problem with these solutions is that the drive wheel constantly drives all the gear wheels present on the orbital path together and so when individual tool units are not intended to be driven it is necessary to provide couplings.
The object underlying the invention is, therefore, to improve a machine tool of the generic type in such a manner that some of the tool units can be driven selectively in a simple manner.
This object is accomplished in accordance with the invention, in a machine tool of the type described at the outset, in that the drive wheel is rotatable about a drive axis which is arranged non-coaxially in relation to the axis, that teeth of the drive wheel move around the drive axis on a flight path which extends relative to the orbital path of the gear wheels such that in a drive section of the orbital path the distances between this and the flight path have the lowest values and are greater in all the other sections of the orbital path and that the teeth are in drive engagement with a gear wheel located in the drive section and extend without contact in relation to each gear wheel located outside the drive section on the orbital path.
The advantage of the inventive solution is to be seen in the fact that as a result of the special arrangement of the flight path of the teeth relative to the orbital path of the gear wheels the possibility has been created of driving only some of the gear wheels present on the orbital path due to the determination of the drive section and it is, therefore, possible, for example, by rotating the turret head to select the gear wheels which engage with the drive wheel due to the fact that they are moved on the orbital path into the drive section and are, consequently, driven whereas all the remaining gear wheels which are located outside the drive section are automatically not driven.
As a result, it is possible in a simple manner to drive only the gear wheels of selected tool units without additional measures, such as couplings, etc., simply due to the fact that they come to rest in the drive section on the orbital path.
In principle, it is possible to position the drive section as required. It is, in particular, possible to position the drive section at different locations of the orbital path in order to, as a result, achieve a great flexibility with respect to the gear wheels to be driven. For this purpose, the possibility of changing the relative position of the flight path in relation to the orbital path is to be provided.
A particularly favorable embodiment on account of its simplicity provides for the turret head to have the same work positions for each driven tool unit insertable into one of the tool receiving means and in the case of each tool unit located in these work positions for its gear wheel to be located within the drive section. As a result, it is automatically ensured that the drive pinion can be driven by the drive wheel when the tool unit is in its work position.
With this solution it is possible to provide as drive position not only a single rotary position of the tool carrier head but rather it is still possible to provide several rotary positions located within an angular area as work positions and so the rotation of the tool carrier head within the angular area defining work positions allows different alignments of the tool unit in relation to the workpiece.
A solution which is particularly preferred on account of its simplicity provides for each tool unit of the tool carrier head to have a work position which is defined by a fixed angular position and in which the gear wheel is located in an orbital station on the orbital path and for at least the orbital station to be located within the drive section.
This solution has the advantage that as a result of the determination of a single work position the gear wheel is always located within the drive section at the same location and, therefore, clearly definable drive ratios, in particular, with respect to realizing the required precision while the tool unit is being driven are present.
In this respect, it is particularly advantageous when only a single orbital station is located within the drive section.
With respect to the geometric realization of the inventive solution, no further details have so far been given. One advantageous embodiment provides, for example, for the gear wheels to be arranged such that their gear wheel axes intersect the axis.
It is particularly favorable when the gear wheel axes intersect the axis with one another in a common point of intersection of the gear wheel axes.
With respect to the position of the drive axis for the drive wheel and the axis, about which the tool carrier head is rotatable, no further details have so far been given. One particularly advantageous embodiment provides, for example, for the drive axis to be arranged so as to be offset parallel to the axis, about which the tool carrier head is rotatable.
Another alternative solution provides for the drive axis to extend at an angle in relation to the axis, about which the tool carrier head is rotatable.
In this respect, it is preferably provided for the drive axis and the axis to intersect in a drive axis point of intersection.
Particularly favorable geometric ratios can be achieved when the point of intersection of the drive axes and the point of intersection of the gear wheel axes coincide.
Furthermore, the position of the drive axis relative to the drive section has not been defined in greater detail. One solution which can be realized particularly favorably provides for the area of the drive axis passing through the drive wheel to extend on a side of the axis, about which the tool carrier head is rotatable, facing the drive section of the orbital path.
The geometric ratios are, in addition, particularly favorable when the drive axis and the axis, about which the tool carrier head is rotatable, are located in one plane.
This plane is preferably oriented relative to the system of axes of the machine tool such that it extends parallel to the X axis of the machine tool.
In the inventive solution it has been assumed that the teeth of the drive wheel engage with the gear wheel located in the drive section but nothing has been said as to how the engagement of the gear wheel with the teeth of the drive wheel is intended to be realizable.
In this respect, it is to be noted, in particular, that with an alignment of the gear wheel which is completely undefined in relation to the teeth the same damage caused by undefined collisions can occur during engagement.
In order to avoid at least rough collisions, it is therefore provided for the tool drive to be designed as a C axis drive controllable by a control. Such a C axis drive allows the drive wheel to be rotated in a defined manner, for example, along with the rotation of the tool carrier head, and, therefore, at least undesired collisions of such a type that two standing sets of teeth, namely the teeth of the drive wheel and those of the drive pinion, collide when they are brought into engagement with one another to be prevented.
It is even more advantageous when the teeth of the drive wheel and the gear wheel to be brought into engagement with them can be brought into a defined rotary position relative to one another prior to their engagement, wherein this defined rotary position is selected such that it reduces collisions.
In order to bring about a defined rotary position of this type, a guide means is expediently provided in addition to the drive of the drive wheel by means of a C axis and this preliminarily positions the gear wheel moving Into the teeth of the drive wheel during the rotation of the tool carrier head such that it can be brought into engagement with the teeth of the drive wheel essentially collision-free.
Such a guide means may be designed in the most varied of ways. This can, for example, operate such that the guide means brings the gear wheel, prior to the engagement with the teeth of the drive wheel, into a defined rotary position relative to the known alignment of the teeth of the drive wheel.
In this respect, it is particularly advantageous when the guide means brings the gear wheel into engagement with the teeth of the drive wheel whilst rotating. This rotary movement during the engagement of gear wheel and teeth has the effect of particularly reducing collisions.
The guide means can, in this respect, be operative only in sections of the orbital path which adjoin the drive section and be inoperative in additional sections of the orbital path so that the gear wheels can have optional rotary positions or, alternatively thereto, defined rotary positions in these additional sections.
One particularly favorable solution provides, however, for each gear wheel to pass through a respective guidance transfer position when leaving the drive section and when entering the drive section and for each gear wheel to be in a constantly defined rotary position in relation to the guidance transfer positions outside the drive section between passing through these guidance transfer positions.
Such defined rotary positions in relation to the guidance transfer positions may be brought about in a particularly advantageous manner in that a guide means is provided which maintains these rotary positions.
This could, for example, be realized in that the guide means takes over the gear wheel in the guidance transfer position and this rotary position of the gear wheel is retained until it reaches and passes through the next guidance transfer position.
This would, however, require the gear wheel to be secured non-rotatably by the guide means when leaving the drive section in the guidance transfer position and be released again with respect to its rotary movement when moving into the drive section while passing through the guidance transfer position.
A solution which can be realized even more advantageously from a constructional point of view provides for the gear wheel to be turned further by the guide means in a defined manner so that the gear wheel, when reaching the respective guidance transfer position, has the rotary position provided for it.
This guide means is preferably arranged so as to be non-rotatable in relation to the tool carrier housing and, therefore, is not rotatable with the tool carrier head.
No further details have been given in conjunction with the preceding explanations concerning the individual embodiments with respect to the arrangement of the drive wheel and the guide means relative to one another.
It would be conceivable, for example, to arrange the drive wheel on one side of the orbital path, in particular, the toothed ring on the oppositely located side. This would, however, result in a synchronous co-rotation of the drive wheel being necessary during the engagement of the gear wheel with the guide means.
It is, therefore, particularly favorable when the drive wheel and the guide means, in particular, its toothed ring are arranged on the same side of the gear wheels or the orbital path of the gear wheels. In this respect, it is possible to arrange the guide means, in particular, its toothed ring on a side of the orbital path facing the tool carrier housing or on a side of the orbital path facing away from the tool carrier housing.
With respect to the relative arrangement of the guide means, i.e., in particular, of the toothed ring of the guide means and the teeth of the drive wheel, no further details have been given in conjunction with the preceding embodiments.
It is, for example, conceivable to arrange the teeth and the toothed ring in the drive section such that the teeth extend on a side of the toothed ring of the guide means facing the drive shaft.
This solution is advantageous, in particular, when the teeth and the toothed ring are arranged on a side of the gear wheel facing the tool carrier housing.
Another advantageous solution provides for the toothed ring of the guide means to extend in the drive section on a side of the teeth facing the drive shaft, wherein this solution is advantageous, in particular, when the toothed ring and the teeth are arranged on a side of the gear wheels or of the orbital path facing away from the tool carrier housing.